Java CodeQL queries for Code Quality

Explore the queries that CodeQL uses to analyze code quality for code written in Java.

Code Quality uses the following CodeQL queries to analyze Java code and detect code quality issues on:

Copilot Autofix suggestions are provided for findings where possible.

Query name Category Severity
Access to unsupported JDK-internal API Maintainability Recommendation
Boxed variable is never null Maintainability Warning
Cast from abstract to concrete collection Maintainability Warning
Class has same name as super class Maintainability Recommendation
Confusing method names because of capitalization Maintainability Recommendation
Confusing overloading of methods Maintainability Recommendation
Constant interface anti-pattern Maintainability Recommendation
Container contents are never accessed Maintainability Error
Inefficient empty string test Maintainability Recommendation
Inefficient String constructor Maintainability Recommendation
Inner class could be static Maintainability Recommendation
Interface cannot be implemented Maintainability Warning
Javadoc has impossible 'throws' tag Maintainability Recommendation
Misleading indentation Maintainability Warning
Missing Override annotation Maintainability Recommendation
Missing space in string literal Maintainability Recommendation
Mocking all public methods of a class may indicate the unit test is testing too much Maintainability Recommendation
Non-case label in switch statement Maintainability Recommendation
Non-explicit control and whitespace characters Maintainability Warning
Possible confusion of local and field Maintainability Recommendation
Spurious Javadoc @param tags Maintainability Recommendation
Subtle call to inherited method Maintainability Warning
Underscore used as identifier Maintainability Recommendation
Unread local variable Maintainability Recommendation
Unused classes and interfaces Maintainability Recommendation
Unused format argument Maintainability Warning
Unused label Maintainability Recommendation
Use of VisibleForTesting in production code Maintainability Warning
Useless null check Maintainability Warning
Useless parameter Maintainability Recommendation
Useless toString on String Maintainability Recommendation
Useless type test Maintainability Warning
Array index out of bounds Reliability Error
Character passed to StringBuffer or StringBuilder constructor Reliability Error
Comparison of identical values Reliability Error
Constant loop condition Reliability Warning
Container contents are never initialized Reliability Error
Container size compared to zero Reliability Warning
Continue statement that does not continue Reliability Warning
Contradictory type checks Reliability Error
Dereferenced expression may be null Reliability Warning
Dereferenced variable is always null Reliability Error
Dereferenced variable may be null Reliability Warning
Direct call to a run() method Reliability Recommendation
Do not call finalize() Reliability Error
Double-checked locking is not thread-safe Reliability Error
Equals method does not inspect argument type Reliability Error
Equals on incomparable types Reliability Error
Equals or hashCode on arrays Reliability Error
Escaping Reliability Warning
Exposing internal representation Reliability Recommendation
Expression always evaluates to the same value Reliability Warning
Hashed value without hashCode definition Reliability Error
Ignored error status of call Reliability Recommendation
Ignored serialization member of record class Reliability Warning
Implicit conversion from array to string Reliability Recommendation
Inconsistent equals and hashCode Reliability Error
Inconsistent synchronization of getter and setter Reliability Error
Inefficient output stream Reliability Warning
Inefficient primitive constructor Reliability Recommendation
Inefficient use of key set iterator Reliability Recommendation
Iterable wrapping an iterator Reliability Warning
Iterator implementing Iterable Reliability Warning
Left shift by more than the type width Reliability Warning
Missing @Nested annotation on JUnit 5 inner test class Reliability Warning
Missing catch of NumberFormatException Reliability Recommendation
Missing format argument Reliability Error
Non-final method invocation in constructor Reliability Error
Non-synchronized override of synchronized method Reliability Warning
Not thread-safe Reliability Warning
Potential database resource leak Reliability Warning
Potential input resource leak Reliability Warning
Potential output resource leak Reliability Warning
Race condition in double-checked locking object initialization Reliability Warning
Reference equality test of boxed types Reliability Error
Result of multiplication cast to wider type Reliability Warning
Safe publication Reliability Warning
Self assignment Reliability Error
Suspicious date format Reliability Warning
Synchronization on boxed types or strings Reliability Error
Type mismatch on container access Reliability Error
Type mismatch on container modification Reliability Error
Unreachable catch clause Reliability Warning
Use of String#replaceAll with a first argument which is not a regular expression Reliability Recommendation
Use of default toString() Reliability Recommendation
Useless comparison test Reliability Warning
Whitespace contradicts operator precedence Reliability Warning
Wrong NaN comparison Reliability Error
Zero threads set for java.util.concurrent.ScheduledThreadPoolExecutor Reliability Recommendation